It is known in the technical sector of packaging that there exists the need to apply onto each product container a corresponding identification label. Also known are apparatus which are able to transfer onto the container individual self-adhesive labels which are mounted on a backing strip and wound on a reel, by means of programmed and controlled unwinding of the said reel and transfer of a label onto the corresponding container which is moving on an associated labeling machine. In this technical sector also well known are so-called “linerless” labels or labels that are not mounted on a backing strip that must be separated from the label when the latter is applied and recovered separately for disposal thereof. These “linerless” labels essentially consist of a single sheet of suitable material, one of the opposite surfaces of which is provided with an adhesive layer for gluing to the container, while the opposite surface is lined with a transparent and non-adhesive varnish designed to prevent adhesion of the continuous strip when wound onto itself. The continuous strip can also be provided with (pre-cut) perforations forming preferential cutting lines suitable for separation of each label from the ones adjacent thereto.
Reference WO 2009/030893 discusses a method and an apparatus for transferring linerless labels to a container moving on a labeling machine along a given path associated with the machine. The apparatus is based on the use of a silicone-lined transfer belt which rotates in a closed loop around two rollers and which conveys the continuous strip of labels in a direction inclined at a suitable angle relative to the plane of displacement of the product onto which the label must be applied. This relative angle essentially allows the label, which advances together with the transfer belt, to come into contact tangentially with the container and, when it adheres by means of contact to the container, to be cut along pre-cut lines by a fixed blade arranged upstream and perpendicular to the belt itself. Although fulfilling its function, this apparatus nevertheless has a number of drawbacks associated mainly with the fact that the labels made of soft and/or thin material tend not to separate from the transfer belt in a reliable and highly repeatable manner, said separation being determined by the radius of curvature of the transfer belt which cannot be reduced beyond a certain limit value.
In addition, it has been found that the surface of the belt, to which the label is attached, tends to become soiled over time, resulting in an unstable relative contact between belt and label. This can cause, at the moment of separation, an incorrect angle with respect to the belt, with the result being that the label is positioned crookedly on the finished product. Moreover, this solution requires that the labels be made of materials that are so rigid that they are unable to follow the small angle of curvature of the drive belt and therefore become separated from it.
The fixed position of the cutting blade moreover has the effect that it is not possible to cut labels with a certain margin of tolerance in terms of their longitudinal dimension. These drawbacks also mean that with the known apparatus it is not possible to reach the high speeds at which the containers travel on most recent labeling machines, said apparatus thus being essentially unsuitable for the present-day production/packaging cycles.